1. Field of the Invention
The invention relates to an ink jet recording apparatus that discharges ink on a recording medium to form an image thereon and in particular, to an ink jet recording apparatus that can collect ink mist generated when ink is discharged.
2. Related Background Art
In a conventional ink jet recording apparatus, when ink is discharged on a recording medium to form an image, fine ink particles not related to forming the image and called ink mist are generated and this fine ink mist is sometimes dispersed in the recording apparatus. This dispersed ink mist adheres to various parts in the recording apparatus to have detrimental influences on the parts. For example, if the ink mist adheres to recording medium carrying means, it causes a stained recording medium, and if the ink mist adheres to an optical sensor, it causes the faulty detection of the sensor, and if the ink mist adheres to a guide member or the like of a carriage of a serial type recording apparatus, it increases resistance to driving the carriage thereby to cause a faulty operation.
A construction is disclosed in which a fan and a filter are provided in an ink jet recording apparatus in order to prevent dispersion of the ink mist, thereby collecting the generated ink mist (for example, see reference document, Japanese Patent Application Laid-Open No. H08-238784). Further, means for collecting the ink mist by an electrostatic force is also disclosed in the document. In these ink jet recording apparatuses, at the time of collecting the ink mist, it is usual to continuously operate the fan or to continuously apply voltage for generating the electrostatic force.
An ink droplet (main droplet) that is discharged from the recording means of the ink jet recording apparatus to form an image on the recording medium is sufficiently large as compared with the ink mist. Thus, even if the ink mist collecting means is continuously operated, only the ink mist is effectively collected.
However, in recent years, the ink jet recording apparatus has been increasingly required to form images of higher definition and in order to form these images of higher definition, the sizes of the main droplets for forming the image tend to become very microscopic. The ink jet recording apparatus using this very microscopic main droplets has presented a problem that when the ink mist collecting means is continuously operated, it has an influence on the fly of the main droplets and reduces the degree of accuracy when the main droplets adhere to the recording medium, thereby degrading the quality of the formed images.
Further, in the above-mentioned ink jet recording apparatus, the ink mist collecting means is continuously operated, so there is presented a problem of consuming more electric power at the time of forming the images.